| Message ID | efc7ec7010784463b2e7466d7b5c02c2cb381635.1736519461.git.asml.silence@gmail.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [1/1] io_uring: sqpoll: zero sqd->thread on tctx errors | expand |
On Fri, 10 Jan 2025 14:31:23 +0000, Pavel Begunkov wrote: > Syzkeller reports: > > BUG: KASAN: slab-use-after-free in thread_group_cputime+0x409/0x700 kernel/sched/cputime.c:341 > Read of size 8 at addr ffff88803578c510 by task syz.2.3223/27552 > Call Trace: > <TASK> > ... > kasan_report+0x143/0x180 mm/kasan/report.c:602 > thread_group_cputime+0x409/0x700 kernel/sched/cputime.c:341 > thread_group_cputime_adjusted+0xa6/0x340 kernel/sched/cputime.c:639 > getrusage+0x1000/0x1340 kernel/sys.c:1863 > io_uring_show_fdinfo+0xdfe/0x1770 io_uring/fdinfo.c:197 > seq_show+0x608/0x770 fs/proc/fd.c:68 > ... > > [...] Applied, thanks! [1/1] io_uring: sqpoll: zero sqd->thread on tctx errors commit: 1593ed0d510769514b648e09f8b7b71cc7fc18ec Best regards,
diff --git a/io_uring/sqpoll.c b/io_uring/sqpoll.c index 6df5e649c413..5768e31e99b1 100644 --- a/io_uring/sqpoll.c +++ b/io_uring/sqpoll.c @@ -268,8 +268,12 @@ static int io_sq_thread(void *data) DEFINE_WAIT(wait); /* offload context creation failed, just exit */ - if (!current->io_uring) + if (!current->io_uring) { + mutex_lock(&sqd->lock); + sqd->thread = NULL; + mutex_unlock(&sqd->lock); goto err_out; + } snprintf(buf, sizeof(buf), "iou-sqp-%d", sqd->task_pid); set_task_comm(current, buf);
Syzkeller reports: BUG: KASAN: slab-use-after-free in thread_group_cputime+0x409/0x700 kernel/sched/cputime.c:341 Read of size 8 at addr ffff88803578c510 by task syz.2.3223/27552 Call Trace: <TASK> ... kasan_report+0x143/0x180 mm/kasan/report.c:602 thread_group_cputime+0x409/0x700 kernel/sched/cputime.c:341 thread_group_cputime_adjusted+0xa6/0x340 kernel/sched/cputime.c:639 getrusage+0x1000/0x1340 kernel/sys.c:1863 io_uring_show_fdinfo+0xdfe/0x1770 io_uring/fdinfo.c:197 seq_show+0x608/0x770 fs/proc/fd.c:68 ... That's due to sqd->task not being cleared properly in cases where SQPOLL task tctx setup fails. Cc: stable@vger.kernel.org Fixes: 1251d2025c3e1 ("io_uring/sqpoll: early exit thread if task_context wasn't allocated") Reported-by: syzbot+3d92cfcfa84070b0a470@syzkaller.appspotmail.com Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> --- io_uring/sqpoll.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)